Channel-surf almost any night of the week in Britain and chances are you'll come across a gruesome crime drama featuring a dark and tortured soul whose brutal, morally repellent deeds make you recoil in horror.

And that's just the detective.

The primetime landscape here is littered with screwed-up sleuths whose inner demons command almost as much attention as the stomach-churning crimes they solve, using methods invariably described as "unorthodox." Such gritty characters are upholders of a grand tradition exemplified by the likes of John Thaw's Inspector Morse and Jane Tennison of "Prime Suspect," the role that helped vault Helen Mirren to international fame.

The troubled investigator is an archetype that continues to enthrall millions of British TV viewers and that, in many ways, distinguishes crime drama in this country from its counterpart across the Atlantic.

Ask an American to name some classic or current crime programs, and most likely the list will include series such as "The Wire," " NYPD Blue," and "CSI." Certainly there've been colorful solo investigators such as Kojak and Adrian Monk, but ensemble crime shows have become a hallmark of American television.

Those programs have been enthusiastically embraced by critics and audiences in Britain as well. But when it comes to producing their own law-and-order dramas, the British are partial to a different approach, one driven by a central detective whose psychological makeup is as much a part of the story as the grisly crimes that he (or, in rare instances, she) sets out to elucidate.

Your typical police protagonist here is often a brooding misanthrope whose ethics are questionable, or at least malleable, in the pursuit of justice. He may suffer from alcoholism, nearly always has a bad temper, can't maintain personal relationships, alienates fellow officers on the force and is occasionally haunted by a terrible secret. He's not above roughing up suspects, or even playing avenger.

Recent examples include John Rebus, the hard-drinking Scottish police detective ("he tests people's patience to the limit," Ken Stott, the actor who portrays Rebus, once described him) and Kurt Wallander, the anguished Swedish cop played by Kenneth Branagh in the BBC's critically acclaimed adaptation of stories by novelist Henning Mankell.

This year has seen the premiere of a raft of new shows that more or less hew to the same formula. In "Luther," actor Idris Elba ("Stringer" Bell in "The Wire") stars as a maverick, sometimes violent London detective who administers his own brand of justice. "Thorne: Sleepyhead" features Det. Inspector Tom Thorne, who can't escape a typically dark past as he investigates a rash of killings of unspeakable cruelty.

"DCI Banks: Aftermath" offers up another melancholic and moody main character, while "Identity" dwells on the shady secret life of a detective played by Aidan Gillen (another "Wire" veteran).

The ubiquitous figure of the tormented cop may actually be a British twist on an American theme, said Mark Billingham, the author of the Tom Thorne books and a producer on the show. "What strikes me is that we have essentially adopted the American private eye and turned him into a cop," Billingham said.

"We don't have that private eye tradition" of hard-bitten gumshoes like Dashiell Hammett's Sam Spade and Raymond Chandler's Philip Marlowe, he said. "Here, private detectives are very sad types who sit around in cars trying to spot people who are having affairs or claiming disability allowance when they're perfectly able to work. Our kind of flawed, haunted mavericks tend to be cops."

Their idiosyncrasies differ — a taste for opera, an addiction to fast food — but beneath the quirks lies a troubled personality whose emotional and professional failings are often writ large, which is how British audiences seem to prefer their crime-fighters.

"Every so often a critic will say, 'Where are the happy, well-adjusted cops?' And someone will write one," Billingham said. "But honestly, people still want the tortured soul; they want the maverick. And you know what? This hasn't changed in a hundred years. Sherlock Holmes couldn't hold down relationships, sat immovable in his room taking drugs, shooting bullets into the wall ….

"It's amazing how easily he transferred into the modern idiom," Billingham added, referring to the new adaptations of Holmes stories that were shown to lavish praise on the BBC earlier this year and are now being broadcast in the U.S.

The three movie-length episodes of "Sherlock" are set in present-day London, and though Holmes (played by Benedict Cumberbatch) is a private detective rather than a cop, he's a brainy misfit who can't connect with others and who doesn't suffer fools — meaning everyone else — gladly. (In the series, Holmes disdains the term "private detective," preferring "consulting detective" instead.) His Watson ( Martin Freeman), too, is a bit off-kilter, a former army doctor plagued by disturbing memories from a tour of duty in Afghanistan.

The plethora of dark police dramas hasn't altogether crowded out the gentler crime fare that still dots the British primetime lineup. New adaptations of Agatha Christie whodunits featuring Hercule Poirot and Miss Marple continue to attract a sizable audience, as does a long-running series about fairly genteel homicide called "Midsomer Murders."

How long that trend will last and how far the moral ambiguities can go before audiences feel too unsettled remain to be seen. For now, at any rate, British viewers appear content to tune in to crime thrillers that make them shudder — at the good guys as well as the bad ones.